Question

The electric field lines on the left have twice the separation on those on the right as shown in figure. If the magnitude of the field at $A$ is $40\,Vm^{-1}$, what is the force on $20\,\mu \,C$ charge kept at $B$?

• A. $4 \times 10^{-4} Vm^{-1}$
• B. $8 \times 10^{-4} Vm^{-1}$
• C. $16 \times 10^{-4} Vm^{-1}$
• D. $1 \times 10^{-4} Vm^{-1}$

Answer 1

Answer: (A)

We know that
$F = qE =20 \times 20 \times 10^{-6}$
$=4 \times 10^{-4} V / m^{-1}$